Toxicity of canola-derived glucosinolates in pigs fed resistant starch-based diets

Effect of different doses of camelina cake inclusion as a substitute of dietary soyabean meal on growth performance and gut health of weaned pigs

Camelina cake (CAM) is a co-product proposed as an alternative protein source; however, piglet data are still limited. This study aimed to evaluate the effect of different doses of CAM in substitution of soyabean meal on the growth, health and gut health of weaned pigs. At 14 d post-weaning (d0), sixty-four piglets were assigned either to a standard diet or to a diet with 4 %, 8 % or 12 % of CAM. Piglets were weighed weekly. At d7 and d28, faeces were collected for microbiota and polyamine and blood for reactive oxygen metabolites (ROM) and thyroxine analysis. At d28, pigs were slaughtered, organs were weighed, pH was recorded on gut, colon was analysed for volatile fatty acids (VFA) and jejunum was used for morphological and gene expression analysis. Data analysis was carried out using a mixed model including diet, pen and litter as factors; linear and quadratic contrasts were tested. CAM linearly reduced the average daily gain from d0-d7, d0-d14, d0-d21 and d0-d28 (P ≤ 0·01). From d0-d7 increasing CAM linearly decreased feed intake (P = 0·04) and increased linearly the feed to gain (P = 0·004). CAM increased linearly the liver weight (P < 0·0001) and affected the cadaverine (P < 0·001). The diet did not affect the ROM, thyroxine, intestinal pH, VFA and morphology. All doses of CAM increased the α diversity indices at d28 (P < 0·05). CAM at 4 % promoted the abundance of Butyricicoccaceae_UCG-008. Feeding with CAM enhanced resilience in the gut microbiome and can be evaluated as a potential alternative protein source with dose-dependent limitations on piglet growth performance.

Do Brassica Vegetables Affect Thyroid Function?-A Comprehensive Systematic Review

Brassica vegetables are widely consumed all over the world, especially in North America, Asia, and Europe. They are a rich source of sulfur compounds, such as glucosinolates (GLSs) and isothiocyanates (ITCs), which provide health benefits but are also suspected of having a goitrogenic effect. Adhering to PRISMA guidelines, we conducted a systematic review to assess the impact of dietary interventions on thyroid function, in terms of the potential risk for people with thyroid dysfunctions. We analyzed the results of 123 articles of in vitro, animal, and human studies, describing the impact of brassica plants and extracts on thyroid mass and histology, blood levels of TSH, T3, T4, iodine uptake, and the effect on thyroid cancer cells. We also presented the mechanisms of the goitrogenic potential of GLSs and ITCs, the limitations of the studies included, as well as further research directions. The vast majority of the results cast doubt on previous assumptions claiming that brassica plants have antithyroid effects in humans. Instead, they indicate that including brassica vegetables in the daily diet, particularly when accompanied by adequate iodine intake, poses no adverse effects on thyroid function.

Genome-Wide Association Study of Phenylalanine Derived Glucosinolates in Brassica rapa

Glucosinolates (GSLs) are sulfur-containing bioactive compounds usually present in Brassicaceae plants and are usually responsible for a pungent flavor and reduction of the nutritional values of seeds. Therefore, breeding rapeseed varieties with low GSL levels is an important breeding objective. Most GSLs in Brassica rapa are derived from methionine or tryptophan, but two are derived from phenylalanine, one directly (benzylGSL) and one after a round of chain elongation (phenethylGSL). In the present study, two phenylalanine (Phe)-derived GSLs (benzylGSL and phenethylGSL) were identified and quantified in seeds by liquid chromatography and mass spectrometry (LC-MS) analysis. Levels of benzylGSL were low but differed among investigated low and high GSL genotypes. Levels of phenethylGSL (also known as 2-phenylethylGSL) were high but did not differ among GSL genotypes. Subsequently, a genome-wide association study (GWAS) was conducted using 159 B. rapa accessions to demarcate candidate regions underlying 43 and 59 QTNs associated with benzylGSL and phenethylGSL that were distributed on 10 chromosomes and 9 scaffolds, explaining 0.56% to 70.86% of phenotypic variations, respectively. Furthermore, we find that 15 and 18 known or novel candidate genes were identified for the biosynthesis of benzylGSL and phenethylGSL, including known regulators of GSL biosynthesis, such as BrMYB34, BrMYB51, BrMYB28, BrMYB29 and BrMYB122, and novel regulators or structural genes, such as BrMYB44/BrMYB77 and BrMYB60 for benzylGSL and BrCYP79B2 for phenethylGSL. Finally, we investigate the expression profiles of the biosynthetic genes for two Phe-derived GSLs by transcriptomic analysis. Our findings provide new insight into the complex machinery of Phe-derived GSLs in seeds of B. rapa and help to improve the quality of Brassicaceae plant breeding.

Toxicity of Canola-Derived Glucosinolate Degradation Products in Pigs-A Review

Canola co-products are widely included in swine diets as sources of proteins. However, inclusion of canola co-products in diets for pigs is limited by toxicity of glucosinolate degradation products. Aliphatic and aromatic glucosinolates are two major classes of glucosinolates. Glucosinolate degradation products derived from aliphatic glucosinolates (progoitrin) include crambene, epithionitriles, and goitrin, whereas indole-3-acetonitrile, thiocyanate, and indole-3-carbinol are the major aromatic glucosinolates (glucobrassicin)-derived degradation products. At acidic pH (<5.7), progoitrin is degraded by myrosinases to crambene and epithionitriles in the presence of iron, regardless of the presence of epithiospecifier protein (ESP), whereas progoitrin is degraded by myrosinases to goitrin in the absence of ESP, regardless of the presence of iron at neutral pH (6.5). Indole-3-acetonitrile is the major degradation product derived from glucobrassicin in the absence of ESP, regardless of the presence of iron at acidic pH (<4.0), whereas thiocyanate and indole-3-carbinol are the major glucobrassicin-derived degradation products in the absence of ESP, regardless of the presence of iron at neutral pH (7.0). In conclusion, the composition of glucosinolate degradation products is affected by parent glucosinolate composition and hindgut pH. Thus, toxicity of canola co-product-derived glucosinolates can be potentially alleviated by modifying the hindgut pH of pigs.

Invited Review: Glucosinolates Might Result in Low Methane Emissions From Ruminants Fed Brassica Forages

Methane is formed from the microbial degradation of feeds in the digestive tract in ruminants. Methane emissions from ruminants not only result in a loss of feed energy but also contribute to global warming. Previous studies showed that brassica forages, such as forage rape, lead to less methane emitted per unit of dry matter intake than grass-based forages. Differences in rumen pH are proposed to partly explain these low emissions. Rumen microbial community differences are also observed, but the causes of these are unknown, although altered digesta flow has been proposed. This paper proposes a new mechanism underlying the lower methane emissions from sheep fed brassica forages. It is reported that feeding brassica forages to sheep can increase the concentration of free triiodothyronine (FT3) in serum, while the intramuscular injection of FT3 into sheep can reduce the mean retention time of digesta in the rumen. The short retention time of digesta is associated with low methane production. Glucosinolates (GSLs) are chemical components widely present in plants of the genus Brassica. After ruminants consume brassica forages, GSLs are broken down in the rumen. We hypothesize that GSLs or their breakdown products are absorbed into the blood and then may stimulate the secretion of thyroid hormone FT3 in ruminants, and the altered thyroid hormone concentration may change rumen physiology. As a consequence, the mean retention time of digesta in the rumen would be altered, resulting in a decrease in methane emissions. This hypothesis on mitigation mechanism is based on the manipulation of animal physiological parameters, which, if proven, will then support the expansion of this research area.